The long term outcome of prophylactic pharmacologic management of children with chronic asthma has not been well delineated. To assess the outcome of children with chronic symptoms of asthma, managed with prophylactic long term medication, it is proposed to systematically and prospectively identify the variables (age, sex, severity of asthma, presence of history of atopic dermatitis, and cigarette smoking, etc.) that relate to the medication requirement for the control of symptoms of asthma. Subsequent requirements for continued prophylactic medication will be studied in a double-blind (theophylline-placebo) controlled trial every 12 plus or minus 1 months during periods when patients' asthma symptoms will be expected to be severe. Further, the effect of short course corticosteroid therapy on bronchodilator responsiveness of children with asthma, whose airways obstruction is initially not responsive to non-corticosteroid medication, will be studied in a double-blind fashion. Subsequent follow-up of patients will show if airway obstruction in children who receive short term corticosteroid therapy is more responsive for longer periods to non-corticosteroid bronchodilators than in those who do not receive corticosteroid.